There are various methods for folding materials known in the prior art.
EP 0 144 526 A1 discloses a method for the press treatment of fabrics. This method makes use of an apparatus having two rotating rollers rotating in opposite directions and at different speeds and being spaced from each other. The fabric to be treated is moving along the two rollers while it is guided by a limiting means disposed between the two rollers. Due to the different rotational speeds of the two rollers, a folded structure of the fabric is created, resulting in a uniform "zigzag" fold structure of the fabric.
EP 0 529 766 A1 discloses a method of pleating articles of clothing. In this method, the garment is pleated, rolled together, twisted and then clamped in a holding device. This holding device then is introduced into an apparatus for thermal treatment, and the garment is simultaneously heat-treated and pleated by means of a saturated current.
The technical publication "Shibori--The Inventive Art of Japanese Shaped Resist Dying", Kodansha Int., 1983, pages 123 to 138, discloses a method of producing dyed patterns on a fabric. In this method, the fabric is wrapped around a bar, a thread is placed around the fabric, the fabric on the bar is pushed together and finally is dyed in this pushed together condition. By way of this method, a pattern is formed on the fabric which is pulled straight again after dying, with the pattern being dependent upon the folded state of the fabric prior to application there of on the bar, the winding density of the thread and on the winding direction.
For manufacturing lamp shades of paper, it is necessary for the paper to adopt a three-dimensional structure, so that the lamp shades formed thereof retain this structure upon conclusion of the method. This means that the shape of the paper lamp shades does not alter any more after manufacture thereof.
The methods described hereinbefore deal exclusively with the folding or pleating of fabrics, and it is apparent in this respect that these methods do not create a three-dimensional structure of the fabrics as it is indispensable, for example, for lamp shades that are not fixed to a carrier grid, but are supported just by a supporting structure.